<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>rem的作用</title>
		<style type="text/css">
			html{
				font-size: 10px;
			}
			div{
				font-size: 2rem;
			}
		</style>
	</head>
	<body>
		我是10px
		<div id="">
			我是20px
		</div>
	</body>
</html>
